Speak No Evil
by A Study in Reichenbach Feels
Summary: Demon!lock. Takes place during The Sign of Three. John invites his old friends Sam and Dean Winchester to his wedding as the other groomsmen, along with Sherlock. As if the tension between Sherlock and the hunters wasn't enough in the first place, a demon has caught wind of the Winchesters and possesses Sherlock to get to them. Where there's a Winchester, there's trouble.


**This is my first crossover! Hope you enjoy it, hunters and Sherlockians alike!**

* * *

"Are you guys almost ready?" John Watson called out from the hallway by the men's dressing room. John hears shuffling from inside the door.

"Yes, John. Don't worry, we'll be out in a minute," Sherlock replied. John huffed threats under his breath and his footsteps faded from outside the door. Sherlock glanced at the other two groomsmen John had chosen to stand for his wedding.

Clearing his throat, Dean Winchester tried to make conversation. "So, uh, how does John know you?"

"Flat mates," Sherlock quickly replied.

"Flat mates? Isn't John getting married?" Dean chuckled and got an elbow in his rib from Sam.

"We _were_ flat mates," Sherlock rolled his eyes.

"We understand," Sam said and glared at his brother.

Dean silently mocked Sam and pinned one of the flowers they were assigned to his chest. "You know," Dean murmured. "It'd be nice to get a suit that actually works for once."

"Stop complaining," Sam scolded.

"Maybe I'd stop complaining if we had better suits."

"Dean, if I have to tell you one more time-"

"OH, SHUT UP!" Sherlock yelled over the quarreling brothers. Sam and Dean stared at Sherlock, but surprisingly remained silent.

"Hey," Dean whispered to Sam after Sherlock had wandered into the bathroom to fix his tie.

"What?" Sam answered.

"I don't think John ever mentioned Sherlock before. Do you remember him?"

Sam shrugged. "Maybe he's a new friend. People do that, you know."

"Do what?"

"Make friends."

"Shut up." Dean slugged Sam's arm.

* * *

After the tension had died down, Dean addressed Sherlock on the matter. "So, um," he glanced at Sam, who nodded, reassuringly. "My brother and I were wondering how you got to know John."

"Through a friend. We solve-used to solve crimes together," Sherlock said without a second glance at the irritatingly chatty groomsman.

"Oh, so you're like police butt buddies?" Dean smiled at his own sense of humor. "You've taken him for a ride downtown, I bet-"

"Dean-" Sam said with unease. Sherlock turned to face his fellow groomsmen. His eyes darted all about the brothers' towering figures as he gathered information from them.

"What?" Dean defended himself against Sam and then turned back towards Sherlock. "So you're police, then?"

"No, I'm a consulting detective. John helps me out on occasion," Sherlock spoke smoothly.

"I see," Dean nodded. "Well, my brother and I are police, too."

"Dean-"

Dean ignored Sam's protests. "Yeah, we work back in the States for-"

"No, you don't," Sherlock said plainly.

"Excuse me?" Dean asked, taken aback.

"You aren't police, it's obvious. There's no reason to lie to me. Don't you know who I am?"

"Not a clue," Dean said bitterly.

Sherlock stepped closer to Dean, their faces just inches from each other. "I guess I'll just show you who I am."

"Whoa, sorry pal, I don't swing that way."

"You're not police. Although the standard police suits are in disgraceful condition, yours are far worse, suggesting you got them from a thrift store or some such shop. However, you do reside in America, your accents nauseously prominent. Now, you two must care about John a lot to come to a wedding that is so far from your home. The question is why would you wear quite possibly the worst suits ever made to the wedding of a man who means so much to you?"

Sherlock paused, observing their faces longer. "Ah, you can't afford anything more top-notch. I see. However, going by the various stains and faint odor of sweat, I think it's safe to assume you two wear these pieces of junk quite often, never within regular reach of a drycleaners."

* * *

"Hey, I don't know what you're playing at, but-" Dean interrupted.

"In light of this," Sherlock continued. "I think it's safe to assume you wear them abroad, for some reason. Neither of you are employed, so-"

"Yes we are. Why would you say that?" Dean spewed.

"Well, you're not exactly the sharpest tool in the shed," Sherlock laughed, unwilling to explain that point further.

"Wha-"

"Moving on," Sherlock circled the brothers. "So, unemployed and wearing cheap suits all the time. This one," he pointed to Dean, "is quite the impulsive liar. Near professional, I'd say. To be that quick to tell a lie, he must have been telling lies since he was a boy. Maybe even taught to lie?" Sherlock paused again to confirm his progress in Dean's green eyes.

"Yes, taught to lie. Now what, I should wonder, do two brothers traveling the States do for a living, hm?"

"How'd you know we travel the States?" Sam asked curiously.

"I saw you pull up in your crap Impala-"

"Oh, hell no! She isn't crap, she's my _baby!_" Dean lunged at Sherlock, but Sam held him back by his collar.

"Oh, please," Sherlock laughed. "If you really held it in such high esteem, you'd keep it in better shape."

"My baby's in PERFECT shape, you son of a bitch!"

"Left tail light is out, oil needs a change, and," Sherlock leaned in. "I'd check those break lines if I were you." Dean glared at the detective and pushed Sam's hand off him.

"Anyway," Sherlock continued. "There's a lot of wear on the car for just going back and forth from employment which, we've established, you don't have. So what would two brothers be doing playing dress-up around the country? Con-men?"

Sam looked at Dean, then back at Sherlock, giving in. "It's part of the job."

"What job is that, then?" Sherlock inquired.

"None of your damn business!" Dean spat.

"We're hunters," Sam answered. Sherlock tilted his head, not understanding what interest a pair of traveling suits would have in shooting bucks. Sam noted Sherlock's expression and shook his head. "No, not that kind of hunter."

"Bounty hunters?"

"No…It's sort of hard to explain…" Sam stuttered.

"We hunt monsters," said Dean. "Ghosts, shape shifters, vampires, zombies, demons… You name it, we've ganked it."

"Dean, couldn't you have broken it a little more softly?" Sam sighed.

"You're the one who let the cat out of the bag, I was just laying the truth on him." Dean said defensively.

"You hunt…monsters? For a living?" Sherlock asked, restraining his laughter.

"Yeah," Sam confirmed. "More or less."

Sherlock let a few chuckles out. "I don't know if you missed out on this as a kids, but monsters aren't real."

"Yet here we are," Dean exasperated. "What we fight is real as hell, and I should know, I've been there."

"Metaphorically."

"No. I've literally been to hell and back," Dean ignored Sherlock's questioning look. "Look it doesn't matter what you think of us. We do what we do no matter what you choose to believe. No matter what anyone chooses to believe. In fact, Sam and I's assurance that monsters are real have probably saved ten times the lives you've saved with your little microscope. John wouldn't even be here today if it wasn't for us."

Sherlock took a step back. "Don't tell me John's in on all this nonsense, too."

"'Nonsense' is what stubborn douchebags use as a word for something they can't explain," Dean fumed. "So, Mr. Smarty-pants, how about you take your speculations and shove them right back up your-"

"Dean." Sam stopped his brother. "What he means to say..."

"I mean to say," Dean jumped back in. "That no matter how smart you think you art, you don't know everything. Maybe, just maybe, there are things other people know more about than you do. And some day, that might just save your life."

Sherlock was stunned, but replied, "Highly unlikely."

Dean was about to go off on another speech, but Sam pulled him by the arm towards the door and shoved him out. "Come on, the wedding's going to start soon." Sam glanced back and mouthed '_Sorry_' to the detective.

* * *

Sherlock wandered to the mirror and gave his hair a rustle. He straightened his tie and took a deep breath. How did John have such idiotic friends?

_I'll have to ask how they met later, _Sherlock noted mentally. _Although, I do suppose it'd be natural for John to have psychotic friends. He shared a flat with me, after all. But monsters? Does John seriously believe in all of this rubbish? _

Sherlock sighed. _It's simply impossible. _

At the moment, something caught his eye. In the corner of the mirror, a black smoke gathered behind him. Sherlock whipped around and stared at the phenomenon, astounded. He opened his mouth to call for the hunters, but as he did so, the inky smoke dived into his throat. Sherlock's eyes widened and his mind became blurry as he lost control of his own body.


End file.
